1. Technical Field
The present invention relates to the field of optical viewing systems and, in particular, to optical viewing systems that simultaneously display images from at least two video sources.
2. Description of the Related Art
Present optical viewing systems, such as those illustrated in U.S. Pat. No. 5,956,180 to Bass et al. (incorporated by reference in its entirety), utilize two viewing screens that each display an image. When viewed, one image appears in front of the other creating a foreground and background effect. This is the result of the observer's ability to perceive depth.
Each eye of an observer perceives an image at a slightly different angle. This parallax enables humans to perceive depth as well as height and width. To simulate depth in a two-dimensional image, the image can be composed of two images slightly offset from each other. By polarizing each of the two images and wearing special glasses, commonly called 3-D glasses, the two images appear to be merged together but now provide the perception of depth. The left eye receives one of the images, the image polarized to correspond to the left lens of the glasses. The right eye receives the other image, the image polarized to correspond to the right lens of the glasses. These images, commonly called stereographic images, thus create the illusion of depth in the image.
Stereographic images can be quite useful with virtual reality systems. Computer-generated images that are commonly two-dimensional can thus include the effect of depth, which makes the images more real, or life-like. Virtual reality systems have a wide variety of uses, such as video gaming and computer simulators.
A number of technologies exist for tracking the position and orientation of an object, such as, U.S. Pat. Nos. 5,453,686, 6,369,564, 6,400,139, 6,624,626 and 6,762,600 assigned to Polhemus Incorporated; U.S. Pat. Nos. 6,681,629 and 6,757,068 assigned to Intersense Incorporated; U.S. Pat. No. 5,831,260 assigned to Ascension Technology Corporation; U.S. Pat. No. 6,266,136 assigned to Advanced Optical Technologies; and U.S. Pat. No. 6,380,732 assigned to Super Dimension Ltd, the teachings of which are incorporated herein by reference.